Ultra-high frequency electronic device



May 8, 1956 BOWEN 2,745,039

ULTRA-HIGH FREQUENCY ELECTRONIC DEVICE Original Filed May 4, 1945 6 Sheets-Sheet 1 FIG 2 FIG. 3

ARNOLD E. BOWEN DECEASZD VIRGIN/,4 C. BOWEN ATTORNEY y 8, 1956 A. E. BOWEN 2,745,039

ULTRA-HIGH FREQUENCY ELECTRONIC DEVICE Original Filed May 4, 1943 6 Sheets-Sheet 2 FIG. 5

FIG. 5A

7 INVENTOFP ARNOLD E. BOWEN DECEASTD V/PG/N/A C. BOWEN H/S EXECUTP/X A T TOPNE V May 8, 1956 A. E. BOWEN 2,745,039

ULTRA-HIGH FREQUENCY ELECTRONIC DEVICE Original Filed May 4, 1943 l 6 Sheets-Sheet 3 lNl/ENTOP ARNOLD E. BOWEN DECEASED V/RG/N/A C. BOWEN H/S EXECUTR/X WWW ATTORNEY May 8, 1956 A. E. BOWEN ULTRA-HIGH FREQUENCY ELECTRONIC DEVICE 6 Sheets-Sheet 4 Original Filed May 4, 1943 lNl/E/VTOP ARNOLD E. BOWEN DECEASED V/RGl/V/A C. BOWEN H/SEXECUTP/X MUM/M A TTOP/VEV May 8, 1956 A. E. BOWEN 2,745,039

I ULTRA-HIGH FREQUENCY ELECTRONIC DEVICE Original Filed May 4, 1943 6 Sheets-Sheet 5 lNl/ENTOR ARNOLD E. BOWEN DECEASED V/RG/N/A C. BOWEN H/S EXECUTP/X VZMM,%A

A 7' TOP/VE V y 8, 9 6 A. E. BOWEN 2,745,039

ULTRA-HIGH FREQUENCY ELECTRONIC DEVICE Original Filed May 4, 1943 6 Sheets-Sheet 6 MAGNET/6 FIELD D/lFfCTEO PIP/11 L EL T0 CATf/Uflf 5/ //v|//v TOR ARNOLD E. BOWEN DECEASL'D l/lRG/N/A c. BOWEN H/S EXECU TR/X A TTORNEV Arnold E. Bowen, deceased, late of Fair Haven, N. .l., by

Virginia C. Bowen, executrix, Bloomfield, N. J as- New York, N. Y., a corporation of New York Original application, May 4, 1943, Serial No. 485,579, now Patent No. 2,530,373, dated November 21, 1950.

Un ed se Ramp 2,745,039 i P atented May 8,1956

I velocity sorting, and energy abstraction in that order and "-signor to Bell Telephone-Laboratories, Incorporated,

Divided and this application September 20, 1950, Serial This invention relates to arrangements for effecting tems, particularly between a stream Dimovin; charged particles such as electrons, and electromagnetic waves guided or enclosed by electrical conductors.

In devices of this type, it is common practice to determine the trajectories of .the charged particles either byenergy interchanges in high frequency electromagnetic sysmagnetrons, an electric field is maintained by impressing t l a. potential between parallel plane plates, while at the same time a magnetic field is maintained parallel to the plates and hence perpendicular to the electric field. It is known that electrically charged particles, upon being exposed to the action of mutually perpendicular'electric i choidal electron trajectories, use has been made, as faras I am aware, only of that part of the energy residing in the transverse component of the electron velocity. In other words, the energy utilized has been taken from the electron during the part of its motion perpendicular to theplanes between which it moves It is a feature of the.present invention that energy is abstracted from the electron when it is traveling parallel to the planes between which it moves. The invention maybeembodied in oscillators, amplifiers, repeaters, and

the like, particularly for high frequency and microwave applications wherever generation, repetition, control, or "amplification of electromagnetic waves is an object.

oscillator-amplifier arrangement;

at successive points along the path of the stream. It is also knownthat velocity sorting may be effected-by variably cunring or deflecting the stream. The arrange- -nieiits of thepresent invention, however, have an advantage not found in" prior devices, namely, that the path of the stream is kept away from the vicinity of the deflecting or controlling electrodes except at those points where the operations of velocity variation, removal of unwanted gpar'ti'cles, and-abstraction of energy are to be effected.

:Ata'result, energy losses and noise currents caused by charged particles striking the deflecting or controlling "electrodes are largely avoided. Other features and advantages of the invention will be evident from the following description. 1 1

.This'applica'tion is a division of the copending application, Serial No. 485,579, filed May 4, 1943, now Patent No. 2,530,373, issued November 21, 1950, and assigned to the same assignee asthe present application. ;L Several illustrative embodiments of the invention are described in detail hereinafter with reference to the accompanying drawings, in which: .Fig. 1 is a somewhat diagrammatical cross-sectional view of a typical mechanism for controlling the trajectories of a succession of charged particles in accordance with the invention; I g I, Figs. 2, 3, and 4 are diagrams showing a variety of prc iportion'ings of the essential'parts of the trajectory control mechanism;

Fig. 5 is 'a"perspective view, partially broken away, showingaii embodiment of the invention in an oscillator? v Fig. 5A is a plan view of the device of Fig. 5; Fig. 6 is a perspective view, partially broken away showin'g an embodiment of the invention in an amplifier;

Fig. 7 is a perspective view, partly diagrammatic, of an embodiment in an electron coupled amplifier; Fig. 8 is a schematic diagram corresponding to Fig. 7; Fig. 9 is a schematic diagram of an electron coupled Figs. 10 and 11 are perspective views of tuned circuit structures adapted for use in various embodiments of the invention; v v

Fig. 12 is a schematic diagram of another form of electron coupled oscillator-amplifier; and

Fig. 13 is a perspective view in longitudinal section showing a repeater in a wave-guide transmission line. The principles underlying the invention are conveniently explained with reference to Fig. 1, wherein are In accordancewith the invention, a stream of charged 60 represented diagrammatically two parallel plane plates particles is constrained to'move' in a trajectory compeculiar to cycloidal or trochoidal motion under substantially constant forces. The regions of relatively high axial speed may conveniently be designated as loops and the intervals of relatively lowor reversed axial speed as nodes, in partial analogy to the alternate loops and nodes, of a vibrating air column. The stream of charged particles is. subjected to a cyclical velocity variation followed by a separation of accelerated and decelerated electrons to form a density varied stream which may be used to excite oscillations ina resonator of suitable form.

In accordance with the invention, the velocity variation and oscillation excitation operations are carried out at loops in the cycloidal path, while the stream is density varied by withdrawing someof the electrons from the stream in a region near a nodalpoint of the path, h

It has already been'proposed to perform upon 'a's'tream prising a series of cycloidal or trochoidal hops, progressing along a predetermined axis. The motion is characterized by the alternate intervals of relatively high forward axial speed and relatively low or reversed axial speed 1 and 2 separated a distance a and maintained at a substantially constant potential difference V0, plate 1 being positive with respect to plate 21 The resultant electric field intensity from the cathode 3. A collector plate 6 is located in therplane of plate-2, insulated. therefrom, and preferably maintained at a potential somewhat positive with respect to? plates2. A substantially uniform magnetic field of of charged particles the operations of velocity variation, q

intensity H is maintained Wlthl-itS lines of force directed perpendicular to'the planeof'the drawing in'the sense away from thereader. the explanation that the uniformity of the fields E'and'H It is assumed for the purpose of is not materially disturbed by any edge effects or by the presence of the cathode 3, the collector 6,-or theslots .4

and 5. Assuming further that electrons are released with zero velocity at the cathode 3, then, according to-known principles, the electrons will travel in trajectories such as that shown in the curve 7, .which is a commoncycloid.

The assumedconditions may readilyzbe approximated in practice.

The equations of motion of an electron in the system of .Fig. 1 are readily set up and the equations of the electron paths undergiven boundary conditions. derived therefrom by' conventional analytical methodsw It is. therefore deemed unnecessary to present a'detailed solution, .and only the basic equations and final results. are set down here.

Assuming a set of mutually perpendicular rectangular coordinate axis X, Y, Z, directed as indicated in .Fig. 1, the equations of motion for an electron of charge 2 and i of mass m are i where c is the velocity of light, and e, E, and H are'to be taken as positive numbers. As the problem is fundamentally one of two dimensions only, it willnot be necessary to consider further the y-coordinate .n'or Equation 2. Additional simplification of the analysis may be had by introducing the following abbreviations:

H j ;=p (4) the use of which makes eE 7-P The equations to be solved then reduce to 4%: dz =PEZ d z dz =P o-a The complete solution of the simultaneous Equations 7 and 8 is In 9 to 14 inclusive, c1, 02,03, and C4- stand for the constants of integration. 1 From the general solutions (9) and (10), aparticular solution may be had for the case of particles starting from rest at th'e'origin at the time when 't is'zero b'y'using the initial conditions represented by dt dt to determine the constants of integration. The result is readily, found to be,

the standard "equ'atio'ns'of a common cycloid.

Referring to the curve 7 in Fig. 1, the left-hand portion of the curve represents the common cycloid of Equations 16 and 17. The curve will have a maximum value of z for the condition .P 1 8) and at this'point it will be found that 7 Assuming that the spacing a has been so chosen that the cycloidal trajectory 7 will just graze the plate 1 it will be evident that the maximum z-coordinate of the trajectory will be equal to a, and it will be found that at pt= 1r,

In accordance with the invention, a velocity variation is impressed upon the particles as they pass the first point of maximum z-coordinate by means of a variable potential difference across the slot 4, which will be suitably superposed upon the initial potential V0 of the plate 1 as a whole. Then the potential which acts upon a given electron causing it to pass the gap 4 may be expressed as V: Vo+6Vn (26) where 6 is a small factor which in ordinary practice will usually lie within limits between 1 and +1. If we assume that a given electron leaves the gap 4 with a speed s determined by the potential V, as given in. (26), then the equation represents the relationship between V and s based upon the conversion of potential energy into kinetic energy. Solving (27) for s andusing (26) gives Using Vo=aE .(29)

together with (25) .and (4), we have i =2 m/i l (30) distant .The trajectory of an electron after it leaves the gap 4 must be ,such as satisfy thewequations of motion (;l), (2)., :and (3) as well as the new initial conditions .prorduced .bythe velocity variation. Theylatter conditions Equations 3.6 and 37 will be recognized as the equations of a 'family of trochoids generated by a movable point,

from the .center of a circle .of diameter .a, which .is rolling upon :and above the .line

The trochoids corresponding, respectively, to the-values, .:6=0.5, 5:0, and 6=+0.-5 are plotted in Fig. l flas In particular, the .result .is found that the transit time -betweenthe gaps 4 and 5 is the same for all the particles regardless of the length and shape of trajectory. Both ranted. I I

*Thevelocityvariation at the gap 4 effects a control these characteristics may be verified by substituting pt='31r in (36) and (37), which gives which expressions ,are independent .of 6 and' determine the above-mentioned common point at the gap 5.-' -The' average speed of any particle while traversing the distance :between the gaps 4 and -5 is the intergapvdistance ara' stream causes an alternating current'to -be induced-in thez:

plate 1. The stream is .given a density variation aby-sthe action of the platei2, .Whichfis so placed as to intercept 'particlesiin a group of trajectories represented by .;curve :10, "while particles ;.in a :group of trajectories represented ibycurve 8' pass on unintercepted. The velocitywvariation" imp zcssctlupon the stream at the gap 4 produces-acyclical variation in: the trajectories of successive particles ranging datum throughtrajectories of the. type of curve .8, the -cycloidal type -9,=the. type of curve 10, the .cyeloidal atype again and back. to the type .of curve .8, etc. Only; the

particles-following trajectories of the type 8 reachthe gap '5, and these form a density varied or intermittent stream ,at the gap 5'. Plate 6 serves to collect :the spent particles'afterthey leave the gap 25. The parts .of the curves 9 and '10 which are unoccupied by particles @because of .interccptionby plate 2 are showndottedxin Fig. 1. *It. will be noted that the mechanism described is .one for transforming a steady stream ofvcharged'particles into an intermittentor density varied stream. alt will be noted further that the grouping of the particles is not dependent upon the principle of fast moving particles overtaking slower moving particles. The principle employed is one of segregating those particles whichexceed a certain critical velocity. p

It will be noted further that the charged' particles' approaching the gap 4 are moving with substantially a uniform velocity and in a direction parallel to the plate 1. This condition might be brought about in various ways other than by locating the cathode 3 in the plane of the plate and using he e haniisrmdesc ibedt r pr ducin t e ycloi al traj ctor Fo ex mp e. t e stream of charged particles might ,be made to-approach the gap 4 along astraight path parallelt'o the plate 1 under the influence of an electricfieldin the absence of the magnetic field H. The mechanism shown and the use of the cycloidal trajectory 7 will ordinarily be simplest and most expedient, but it will be .understood that {it {is within '-pendicular to the plane common to the electric and magnetic vectors. In the neighborhoods of gap 4 and gap 5, :the :pefiiodiecor'nponent of motion in t-hefdireotion o'f the electric force produces a maximum displacementincompliance with the electric field. In the region where certain of the trajectories meett-helground plate 2, the particles are moving in opposition to the electric field. In the case of trajectories of ,the type ofcurve 10, there is superposed upon the drift motion an incidental periodic componentfwhich could be utilized if circumstances warover the periodic "motion in the direction of the'electric force, namely, a control of the amplitude of such periodic motion. Under the variable amplitude condition,

however, all the variation :is confined to the region in which the particles move against the force,of the electric "field, as described, the excursion ,of the particles in ,cornplianc'e with the electric forcebeing Iimite'd to e 1m maximum value a by the combined eifect 'ofthe' electric and magnetic fields. V

In the operation of .the device as .an amplifier, the

potential of the gap 4 is varied by means of the wave to be amplified, and the output resonator is connected across the gap 5. The spacing 1rd, between the gaps; and 5, as seen from (25) is a function of both E and H, varying directly as E and inversely as the square of Thetransittinie between-the gapsis I H U:

and varies inversely with H, independently of E. There is, moreover, no critical transit time required in the am- Plifier case. I i

In the operation of the device as an oscillator, the available values of H are limited once the frequency of the desired oscillation is determined It has been shown above that the particles which pass the gap when the plate 2 is in place are those which aredecelerated at the gap 4. In order for these particles to contribute energy to the field at the gap 5, the particles must pass gap 5, while the field is opposing their motion. In a case where the gaps 4 and 5 are excited in such manner that the fields at the "two gaps are poled in the same direction, an integralnumber of periods of the oscillation should elapse between the passage of a particle across the gap 4 and its I subsequent passage across the gap 5.

In terms of the frequency f, the relation jp eH must hold, where n is any integer or, in terms of the free space wavelength A,

It will be noted that in a given device of this type, m, c, and e are natural constants, and the product AH is dependent upon these constants as well as upon the value of n which may be chosen. Thus,

in which formula A is to be expressed in centimeters and 'H and in electromagnetic units. The same thing with H in oersteds is 2armc which, when the charged particles are electrons becomes approximately It will be evident from Equation 47 that the larger the value of n selected, the smaller the value of H required for oscillations of a given wavelength.

The value of the spacing a between the platesv as given by 25 may be expressed in terms of V0 as follows:

which formula is applicable either to an amplifier 'or an oscillator. Since, in the case of the electron oscillator,

are in electromagnetic units, x is in centimeters, and e=3 X centimeter/ seconds, or

centimeters (50) where). is incentimeters and V0 in volts.

' 8 A number of examples coming out of Formula 50 have been computed and are shown diagrammatically in Figs.

'2, 3, and 4. It will be noted that for given values of hand V0, the spacing a is proportional to n.

made, at the same time changing n so that the required spacing remains the same. For example, in Fig. 2, if n is made 2 and the wavelength and spacing remainunchanged, the voltage must be reduced to one fourth its former value. The change in n also requires that H be reduced to one half its former value in order that 47 may be satisfied.

Several possible combinations of values for a 10-centimeter wavelength in the diagram of Fig. 2 are tabulated in Table I.

Table l a, cm n V volts H, oersteds A, cm

' Several posible combinations for a lO-centimeter wavelength in the diagram of Fig. 3 are given in Table II. 1

Table II a, cm 1 V0, volts H, oersteds A, cm.

Combinations for the diagram of Fig. 4 are given in Table HI. I

Table III a, cm n V0, volts H, oersteds A, cm

Conductors 14', 15', and 16 of a resonant circuit are shown schematically connecting the plate segments 1' in Fig. 2. To indicate resonance at the same wavelength in Figs. 3 and 4 as in Fig. 2, the areas enclosed by the conductors are shown approximately equal in all three figures.

Fig. 5 represents an embodiment of the invention in an oscillator complete with a resonating circuit, an output coupling device, and means for supplying the requisite electric and magnetic field intensities. The equivalent of the plate 1 of Fig. 1 is represented in Fig. 5 by a threesegment anode having segments 11, 12, and 13 connected together by conductors 14, 15, and 16, the latter, together with the anode segments, comprising a resonant circuit. The inductance of the resonant circuit resides mainly in the conductors 14, 15, and 16, while the capacitance is mainly between segments 11 and 12 at the gap 4 and between segments 12 and 13 at the gap 5. The negative or ground plate 2 has a depression in which the cathode 3 is insulatingly mounted. These parts, together with the collector plate 6, are supported byrods '9 held in a 'press 17 of conventional 'typeformed 'in the wall of .a vacuum-tight container .18, which wall may, for example, be of glass} The supporting rods may serve also as electrical connections from the plates to the sources of electromotive'force. 'The latter sources may constitute batteries or other suitable devices, "of which 19 serves to heat the cathode, 20 to polarize the anode segments 11, 12, :13 :positively'with-respect to 'thezground plate 2, and 21 serves to "maintainthe collector '6 prefer- :ably at a somewhatpositive potential with respect to the plate 2. Coupled to the conductors 14 and 16.is a coupling loop 22, the ends of which 'mayzproject through the envelope '18 and be connected to :any suitable load do- I vicefor-transmitting or utilizingthe generated'oscillations,

the load circuit here being respresented by a resistor 23. An electromagnet comprising pole-pieces 24, winding 25, a yoke 26 and energized 'by suitable means, such. as a battery 27, is provided, preferably external to the envelope 1'8, and is set up in such a position (Fig. A) as to .pro-

"vide a magnetic field having lines of force substantially parallel to the cathode 3 and the several plates.

The cycloidal path of a typical electron leaving the cathode 3 and approaching the gap 4 is'shown at 7. The path of this electron, should it be dccelerated at the gap 4, 'isindicated at'8' showing that its trajectory continues past the gap 5 and preferably ends upon the collector plate-6. Should the same electron instead be accelerated .at the gap -4, its path is indicated at 10', ending upon the ground plate 2 and not reaching the gap 5.

The spacing between the ground plate and the anode is determined as described hereinbefore in connection with Fig. 1 for a desired operating wavelength at a given voltage and for achosen value of n according to (50). The

resonator is proportioned to be resonant to the operating wavelength. Further details of the operation of the sys temcf Fig. 5 will be evident from the explanation given --hereinabove in connection with Fig. 1.

Fig. 6 illustrates an embodiment of the invention in anamplifier. In the arrangement of Fig. 6,'the conductor used in Fig. 5 is replaced by a conductive plate- -42. The conductors 14 and 16 are replaced, respectively,

vby conductors-43 and 44 connected to opposite sides of the .-plate 42. An input coupling loop 45 is arranged adjacent the conductor 43. The collector plate 6 may be insulatingly mounted upon a shoulder cut in the ground .plate :2, as shown. Waves to be amplified may be sup- .plied by a source 46 connected to the loop 45. The impressed oscillations serve to set up alternating potentials across the gap 4. The amplified oscillations are setup in the resonant circuit including the conductor 44. A

coupling loop 47 is mounted adjacent the conductor 44 and is connected to a load device 48. The detailed operation of the system of Fig. 6 as an amplifier will be readily understood from thedescription hereinabove given in connection with Fig. 1.

In an alternative mode of operation of devices in-accordance with the invention, the faster group of electrons may be utilized in the excitation of the output circuit in .place of the slower group. This mode of operation may be used with a smallaccompanying reorganization of the apparatus. Fig. 7 shows an amplifier arranged to etfect excitation of the output circuit by means of the 'faster' group of electrons. The chief modification comprises the placing of the input and output circuits on opposite sides of the ground plate in the form of separate anodes. .Each anode may comprise two segments defining .a sin- .gle gap. It may be necessary in some cases to provide increased separation between the ground plate and the col- 'lector in order to accommodate the passage of accelerated electrons therebetween in a variety of trajectories.

In the arrangement of.Fig. 7, a vacuum container is represented schematically by a broken line 50. 'The leads 'by which the energizing and biasing potentials are applied to the various electrodes within the vacuum compartment are shown for simplicity'by solid'lines crossing the boundary-50. :For simplicity, also, the energizing sources 'of electromotive force have *been :omitted, :since they may be readily supplied, as shown in "Figs. 5 and 6. A cathode 51 is represented as supplied "by heating :leads :52 and 53. -A ground plate 54 is provided with ;a

groove for accommodating the-cathode51. "Externaltconnection to the ground plate is provided by means of .a lead .55. A source of high frequency waves to be amplified is represented by a .generator'56, coupled by means of a loop 57 to an input tuned circuit comprising :two

anode segments 58, 59 joined by a conductor 60. .A;suitable positive potential may be impressed upon the -system 58, 559, 60 by means of a lead 61 preferably symmetrically disposed, as shown. A collector'62 is provided inzthe same plane as theaground pl-ate 54 and is connected to a lead 63. On the opposite side of the ground plate from the system 5860 is providedan-output tuned circuit comprising two anode segments 64, 65 joined by a conductor :66. vAn output .loop 67 isprovided tin inductive relation to thetconductor -66 and has its ends led out to a load circuit which is represented by'a resistor68. A suitable positive potential may be impressed upon the anode system 64--66 through ahlead 69.

In the operation of the systemcf Fig. 7, the typical electron leaving the cathode 51 travels in a :cycloidal trajectory 7 and in passing the vicinity of the gap 58, 59, the electron receives a velocit-yvariation due/to theimpressed waves :from the generator 56tacting through the 'coupling'system57 to 60, inclusive. Theaccelerated'electrons pass through the gap between plates 54 and 62,

and, as they emerge, they come :into the field between the ,ground'plate'and the-output anodeisystem.64,-65,.66. An accelerated electron thus emerging follows atgenerally cycloidal trajectoryv 70, which carries it .to the yicinity .ofthegap between the anode segments ".64, '65 and finally causes the electron to strike the lower side of the ,plate '54, as' shown. The-.decelerated electrons ;are carried past the gap .54 to 62, inclusive, to the collector62. The accelerated electrons, thus separated from the ldecelerated electrons, form anzintermittentor density varied stream which serves to excite .the output tuned circuit as the stream passes .the vicinity of the gap 64, 65.

Fig. 8 .is a simplified schematic representation of the arrangement ofFig. 7, the elements being correspondingly numbered in the two figures.

Other modificationsof the structures hereinabove --.de-

scribed enable thesystem-to-rbe adapted -for useas a .masteroscillator-amplifier combination -in which the cou' ,pling between the oscillator andtheamplifienis effected by means .of the-electronstream. Thereris'thus provided what is commonly termed an electron-coupled oscillator. Examples-of thisare shown-in Figs. 9 and.l2-by meansof simplified schematicrepresentations.

In Fig. 9, there is shown within a vacuum container .71 a ground plate 72 having onone side thereofza cathode 73 and:a tuned circuit 74 of the three-segment anode type disclosed in Fig. 5. Coplanar with the groundplate 7.2-.is a collector plate 75. 0n thereverse sideof the ground plate 72.from.the-cathode'-73 is an output tuned circuit ,76

whichin turn supplies oscillations to-the load '78tthrough the coupling loop 77. Theload .78 may be varied without disturbing .to any appreciable extent'the operating conditionsof theoscillator section. Therefore, the .loadlhasa minimum of disturbing eifectuponthefrequency of 111 oscillator. r

Fig. shows a tuned circuit comprising a pair of anode segments 104 and 105 joined by an inductive conductor 106. The arrangement is mounted so that the plates 104 and 105 are coplanar with a guard plate 107 and are positioned in an opening therein. The conductor 106 is conductively connected to and supported by a conductor 108, which is in turn conductively connected to and supported by the plate 107. The conductor 108, while it may represent an appreciable inductance, can still serve as an untuned connection between the conductor 106 and the plate 107. It is only necessary that the systern 107, 108 shall not support electromagnetic oscillations at a frequency in the neighborhood of the desired operating frequency. Under this condition, the anode segments 104 and 105 may sustain an alternating potential, while the plate 107 and connector 108 will remain at a substantially unvarying potential.

Fig. 11 shows a tuned circuit which is a modification of that shown in Fig. 10. A guard plate 107' has two openings within which the plates 104 and 105 are positioned, respectively. The conductor 106 connects the plates 104 and 105, as in Fig. 10, and a conductor 108' connects the middle of the conductor 106 to the portion of the plate 107 between the two openings.

In Fig. 12 is shown an arrangement generally similar to that of Fig. 9 and containing several added features. There is shown within the vacuum container 71 a ground plate 72 having on one side thereof a cathode 73 and a tuned circuit 74. Coplanar with the ground plate 72 is a collector. plate 75. On the reverse side of the ground plate 72 from the cathode 73 is an output tuned circuit 76. A coupling loop 77 is provided in inductive relation to the circuit 76 and is connected to a load 78. The tuned circuit 74 may be of the type shown in Fig. 11, the broken lines 86 and 87' representing conductive connections effected within the body of plate 107 of Fig. 11. The tuned circuit 76 may be of the type shown in Fig. 10, broken lines 86, 87 and 88 representing the conductor 108 of Fig. 10, and full lines 84 and 85 representing the plate 107 in Fig. 10. The ground plate 72 is in two sections separated by a gap and connected by an untuned conductive connection 89. Opposite the gap in the plate 72 is provided a grid 90 which may be used for modulation or other control purpose. An additional collector 91, 92 is arranged in the plane of the plate 72. The direction of the magnetic field is indicated symbolically by H.

In the operation of the arrangement of Fig. 12, the tuned circuit 74 may be kept at a desired positive potential with respect to the plate 72. The tuned circuit 76 may be kept at a different positive potential with respect to the plate 72. By properly arranging the spacing of the respective plates, the system may be operated with a higher potential in the amplifier section than in the oscillator section, if desired. 7

Fig. 13 shows in longitudinal section an adaptation of the arrangement of Fig. 8 which enables the device to operate as a repeater in a wave-guide transmission sys tem. The wall of a wave guide is shown at 93. A resonant section of wave guide, preferably constituting a half wavelength resonator, is defined by iris diaphragms represented schematically at 94 and 95. Diaphragm 94 may be variable as to the size of the aperture, and diaphragm 95 may have a fixed aperture hermetically sealed by a window 96 of dielectric material. Similar elements 94', 95', and 96' may be provided to determine another half-wave resonator and a chamber 97 between the diaphragms 95 and 95. In the chamber 97 may be located a cathode 51, a ground plate 54, and a collector 62, similar to the corresponding elements shown in Fig. 8.

In the operation of the arrangement of Fig. 13, the apertures in the diaphragms 95 and 95' correspond, respectively, to the gaps in the input and output tuned circuits of thearrangement of Fig. 8. A wave transmitted from left to right through the wave guide will be resonated in the chamber between the diaphragms 94 and 95 and will impress an alternating potential across the input gap. The output potential will be impressed across the output gap and will act through the Window 96' to set up an amplified wave in the resonator between the diaphragms and 94. The amplified wave will be transmitted through the aperture of the diaphragm 94' and be propagated along to the right through the wave guide. 1

While means for supplying the necessary steady component of magnetic field are shown only in Fig. 5, it will be understood that suitable means for this purpose are to be supplied in each arrangement illustrated. Mechanical supports for the elements have also been omitted from several of the figures in the interest of focusing attention upon those features which form a part of the present invention.

What is claimed is:

1. An electron coupled oscillator-amplifier combination comprising a ground plate, a cathode on one side only of said ground plate, a resonant system of conductors defining a first gap and a second gap, said system being located generally opposite the ground plate and on the same side thereof as the cathode, means to constrain electrons from said cathode to travel in curved paths which vary in curvature depending upon the velocity of the electrons and which pass through and beyond the neighborhood of said first gap, whereby any alternating electromagnetic field which may be developed in said gap by excitation of said resonant system serves to velocity vary the electron stream to divide the electrons as they pass said gap into first and second density varied streams which follow paths of unequal curvature, said second gap being positioned adjacent the path of said first density varied stream whereby this stream induces an alternating electromagnetic field in said second gap thereby generating self-oscillations in said resonant system, a collecting electrode adjacent to said ground plate and in the path of-the said first density varied stream beyond the region of said second gap whereby said first stream strikes said collecting electrode, means including an edge of said ground plate defining an opening located in the path of said second density varied stream through which the said second density varied stream passes into a region on the other side of the ground plate from the cathode, and energy abstracting means positioned along the path of the said second stream in said last-mentioned region spaced from the ground plate in the direction of the thickness of the said plate, whereby self-oscillations of the said resonant system on the cathode side of the ground plate are maintained and transferred by electronic coupling to the system on the other side of the ground plate.

2. An electron coupled oscillator-amplifier combination comprising a ground plate having a gap therein, a cathode on one side only of said ground plate supplying electrons of substantially uniform initial velocity, a resonant system of conductors defining a first gap and a second gap, the aforementioned gap in the ground plate being designated hereinafter as the third gap, said resonant system being located generally opposite the ground plate and on the same side thereof as the cathode, means to constrain electrons from said cathode to travel in curved paths which vary in curvature depending upon the electron velocity and which pass through and beyond the neighborhood of said first gap, whereby any alternating electromagnetic field which may be developed in said gap by excitation of said resonant system serves to velocity vary the electron stream to cause the electrons after they pass said gap to follow paths of unequal curvature, constituting first and second density varied streams respectively, said second gap being positioned adjacent the path of said first density varied stream whereby this stream induces an alternating electromagnetic field in said second gap thereby generating self-oscillations in said resonant system, a collecting electrode adjacent to said ground plate and in the path of the said first density varied stream beyond the region of said second gap whereby said first a 14 stream strikes said collecting electrode, said third gap tained and transferred by electronic coupling to the system being positioned in the path of the said second density on the other side of the ground plate.

varied stream beyond the region of said first gap whereby References Cited in the file of this patent said second stream passes into a region on the other side I of the ground plate from the cathode, and energy abstract- 5 UNITED STATES PATENTS ing means positioned along the path of the said second 2,221,467 Bleakney Nov. 12, 1940 stream in said last-mentioned region spaced from the 2,321,912 Hedberg June 15, 1943 ground plate in the direction of the thickness of the said 2,414,121 Pierce Jan. 14, 1947 plate, whereby self-oscillations of the said resonant sys- 2,428,612 Blewett Oct. 7, 1947 tem on the cathode side of the ground plate are main- 10 2,444,242 Blewett June 29, 1948 

